This invention relates to ignition timing controllers for an internal combustion engine.
In recent years there has been a strong demand for ignition systems which are more precise and stable in ignition timing than has hitherto been realized, so that the exhaust gas of the internal combustion engines can be made cleaner and the output power of the internal combustion engines can be further increased. For this reason conventional contact breaker type ignition systems are being replaced by the fully electronic or transistorized systems which do not use contact breakers.
Although in these electronic ignition systems the ignition timing signals are produced by an ignition timing signal generator which does not utilise breaker contacts (namely, by signal generators such as those utilizing magnetic inductive coils or Hall-effect devices), the timing signal generator is included in the distributor which is driven mechanically by the crankshaft of the internal combustion engine, for example through a timing belt, as was also the case with conventional contact breaker type ignition systems.
Therefore, deviation of the ignition timing signals from the normal positions thereof in a cycle of the internal combustion engine such as may occur due to various causes would increase and become more apparent as time goes by, due, for example, to the aging of the distributor drive mechanism. This deviation of the ignition timing signals from the normal positions thereof, which is also conspicuous in the idling state of the internal combustion engine, greatly and adversely affects the composition of the exhaust gas and the output power of the internal combustion engines.
In conventional ignition systems as hereinabove described, the deviation of the ignition timing from the normal positions thereof in the cycle of the internal combustion engine due to manufacturing errors within a permitted tolerance for the distributor and the internal combustion engine, is corrected by initial adjustment of the rotational angle of the distributor with respect to the driving shaft thereof which is driven by the crankshaft of the internal combustion engine. For this reason, the portion of the distributor which is mounted to the driving shaft thereof has a structure capable of rotation for adjustment purposes. This structure is convenient for periodical adjustments of the internal combustion engine which should be carried out at regular time intervals. But this structure also allows a person having certain knowledge in the art to deliberately advance the ignition timings from the normal positions thereof in the cycle of the internal combustion engine, so that the output power of the internal combustion engine can be increased. But this deliberate misadjustment adversely affects the the composition of the exhaust gas of the internal combustion engine.
Thus the conventional ignition systems have suffered from deviations of the ignition timings from the normal positions thereof in the cycle of the internal combustion engine, due to various causes, as hereinabove described so that the composition of the exhaust gas of the internal combustion engine is adversly affected by said deviations.